package org.demo.test;


import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;

import javax.media.opengl.GL;
import javax.media.opengl.GLAutoDrawable;
import javax.media.opengl.GLCanvas;
import javax.media.opengl.GLCapabilities;
import javax.media.opengl.GLEventListener;
import javax.media.opengl.glu.GLU;
import javax.swing.JFrame;

/**
 * When the left mouse button is pressed, this program reads the mouse position
 * and determines two 3D points from which it was transformed. Very little is
 * displayed.
 * 
 * @author Kiet Le (Java port)
 */
public class Unproject
  extends JFrame
    implements GLEventListener, KeyListener, MouseListener
{
  private GLU glu;
  private GLCapabilities caps;
  private GLCanvas canvas;
  private MouseEvent mouse;


  public Unproject()
  {
    super("unproject");

    caps = new GLCapabilities();
    canvas = new GLCanvas(caps);
    canvas.addGLEventListener(this);
    canvas.addKeyListener(this);
    canvas.addMouseListener(this);

    getContentPane().add(canvas);
  }

  public void run()
  {
    setSize(500, 500);
    setLocationRelativeTo(null);
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    setVisible(true);
    canvas.requestFocusInWindow();
  }

  public static void main(String[] args)
  {
    new Unproject().run();
  }

  public void init(GLAutoDrawable drawable)
  {
    GL gl = drawable.getGL();
    glu = new GLU();    
  }

  public void display(GLAutoDrawable drawable)
  {
    GL gl = drawable.getGL();
   
    gl.glClear(GL.GL_COLOR_BUFFER_BIT);

    int viewport[] = new int[4];
    double mvmatrix[] = new double[16];
    double projmatrix[] = new double[16];
    int realy = 0;// GL y coord pos
    double wcoord[] = new double[4];// wx, wy, wz;// returned xyz coords
    
    if (mouse != null)
    {
      int x = mouse.getX(), y = mouse.getY();
      switch (mouse.getButton()) {
        case MouseEvent.BUTTON1:
          gl.glGetIntegerv(GL.GL_VIEWPORT, viewport, 0);
          gl.glGetDoublev(GL.GL_MODELVIEW_MATRIX, mvmatrix, 0);
          gl.glGetDoublev(GL.GL_PROJECTION_MATRIX, projmatrix, 0);
          /* note viewport[3] is height of window in pixels */
          realy = viewport[3] - (int) y - 1;
          System.out.println("Coordinates at cursor are (" + x + ", " + realy);
          glu.gluUnProject((double) x, (double) realy, 0.0, //
              mvmatrix, 0,
              projmatrix, 0, 
              viewport, 0, 
              wcoord, 0);
          System.out.println("World coords at z=0.0 are ( " //
                             + wcoord[0] + ", " + wcoord[1] + ", " + wcoord[2]
                             + ")");
          glu.gluUnProject((double) x, (double) realy, 1.0, //
              mvmatrix, 0,
              projmatrix, 0,
              viewport, 0, 
              wcoord, 0);
          System.out.println("World coords at z=1.0 are (" //
                             + wcoord[0] + ", " + wcoord[1] + ", " + wcoord[2]
                             + ")");
          break;
        case MouseEvent.BUTTON2:
          break;
        default:
          break;
      }
    }

    gl.glFlush();
  }

  /* Change these values for a different transformation */
  public void reshape(GLAutoDrawable drawable, int x, int y, int w, int h)
  {
    GL gl = drawable.getGL();
    
    gl.glViewport(0, 0, w, h);
    gl.glMatrixMode(GL.GL_PROJECTION);
    gl.glLoadIdentity();
    glu.gluPerspective(45.0, (float) w / (float) h, 1.0, 100.0);
    gl.glMatrixMode(GL.GL_MODELVIEW);
    gl.glLoadIdentity();
  }

  public void displayChanged(GLAutoDrawable drawable, boolean modeChanged,
      boolean deviceChanged)
  {
  }

  public void keyTyped(KeyEvent key)
  {
  }

  public void keyPressed(KeyEvent key)
  {

    switch (key.getKeyCode()) {
      case KeyEvent.VK_ESCAPE:
        System.exit(0);
        break;

      default:
        break;
    }

  }

  public void keyReleased(KeyEvent key)
  {
  }

  public void mouseClicked(MouseEvent e)
  {
  }

  public void mousePressed(MouseEvent e)
  {
    mouse = e;
    canvas.display();
  }

  public void mouseReleased(MouseEvent e)
  {
  }

  public void mouseEntered(MouseEvent e)
  {
  }

  public void mouseExited(MouseEvent e)
  {
  }

}
